Aerial target



April 1962 w. B. HENDERSHOTT 3,030,111

AERIAL TARGET Filed Dec. 2, 9 8

lullllllllllw" INVENTOR.

WILLIAM B. HEN DERSHOTT triangular..surfacesoriented at 90 to each other.

3,930,! l 1 Patented Apr. 177,

3,030,111 AERIAL TARGET William B. Hendershott, Warminster, Pa., assignor to the United States of America as represented by the Secretary of the Navy Filed Dec. 2, 1958, Ser. No. 777,800 Claims. (Cl. 273-105.3) (Granted under Title 35, US. Code (1952), sec. 266) The invention herein described may be manufactured and used by or for the Government of the United States vof America for governmental purposes without the payment of any, royalties thereon or therefor.

This invention relates to aerial targets and more particularly to tow targets which can be pulled at relatively high speeds as compared to known aerial targets such as the sleeve target, which is incapable of being towed at ,high speeds.

In the past aerial targets, such as the sleeve and banner targets, could be towed at only relatively low speeds as compared to the high speeds of supersonic aircraft. These relatively slow targets are not satisfactory as gunnery targets for training gunners or pilots of supersonic aircraft.

One of the reasons the prior art slow targets have been generally unsatisfactory is due to their general instability and lack of strength at very high speeds. The overall construction of most prior art slow targets is not sufiicientlyrigid to withstand distortion while being towed in relatively sharp turns at high speeds. Any distortion of the target generally causes undesirable additional strains on the towing aircraft. Targets of heavier construction for high speed operation have been built and I used. However, it has been found that if the target is made of heavy construction to withstand high air speeds, trouble will be experienced in unstable lateral oscillations v due. to the high mass and moments of inertia. In addition, a still more important disadvantage of theitargets of known construction, is that increases in targetsize results in proportionate drag increases. This has been found tobe characteristic of the twin-delta type of tow target configuration, which consists of two symmetrictal T e disadvantage of the twin-delta type of target is that an I increase in target size by 50% results in anapproximate drag increase of 50%; This is undesirable.

The presentinvention contemplates the provision of a high speed" aerial target which obviates the above clis advantages. i

Consequently, one, of the principal objects of this inadequate stabilizing surfaces so as to provide an aerodynamically stable target having a large flat target surface for gunnery practice.

A still further object of the invention is to provide a tow target which is of a flat panel construction that can be satisfactorily stabilized at high speeds without having to resort to the twin-delta type of construction.

Yet another object of the invention is to provide a high speed aerial target capable of being towed at very high speeds, which aerial target is adapted to be connected to the tow cable at its center of gravity so that the tow targetis efficiently towed.

Another object of the invention is to provide a high speed tow target, which target is of a rigid, economical and easily manufactured panel construction. Since all tow targets are expendable, it is desirable that the cheapest construction which can be suitably provided be adopted. This is aided by the present invention which permits the user a choice of the desired panel material and a considerable saving in weight can be obtained by the proper selection of panel material.

The invention further resides in certain novel features of construction, combinations and arrangements of parts, and further objects and advantages of the invention will be apparent to those skilled in the art to which it pertainsfrorn the following description of the present preferred embodiment thereof described with reference to the accompanying drawings, which form a part of the specification, and wherein the same reference characters represent corresponding parts throughout theseveral views, and in which:

FIG. 1 is a plan view of an aerial target embodying the invention;

'FIG. 2 is a side elevation view of FIG. 1;

FIG. 3 is an end elevation view of the empennage of FIG. 1;

FIG.4 is a section view along line 44 of FIG. 2; and

FIG. 5 is a fragmentary view of a modification of the invention. f

It is to be understood that the invention is not limited to the details of construction and arrangements of parts shown in the drawings and hereinafter described in detail,

7 but is capable of being otherwise embodied and of being .vention is to provide a'stable, high speed aerial target for v aerial gunnery, and weapons systems evaluation.

' Another ,object ,ofthe invention is to provide a high speed aerial target in .which the increase in target size is not accompanied by a corresponding increase in drag.

,Yet another object {of theinvention is' to provid e a high speed aerial target which has the'minimumfamount of drag surface, and more particularly is provided. with an i aerody namically stable. empennage of a minimum amount of drag surface.

Afurther object of the invention is ,to provide an aerial target capable of being pulled at sonic speeds and .,which target is of such, a rigid and comparatively 'light construction that very little distortion will occur during .the use; of. :the .target.

Another important, advantage of (a high peed aerial target of the .foregoingcons'truction isthat flutter and vibrations of any consequencef will not the amplified in the frame of the targetto a; degree that vmayproyedeleterious to the efficient, ;use ther' eof.

.A ;still furthemobject ,of the present inventionis ;to .provide an ,aeriaLtarget whichpresentsyery little, drag surface and is of arigidtconstmctiombut .WhiClLWill'hEiVG of the empennage 12,

practiced or carried out in various ways. It is to be further understood that the phraseology or terminology employed herein is for the purpose .of description and there is no intention to herein limit the invention beyond the requirements of the prior art.

Referring to FIGS. 1 to 3, a high speed aerial target, embodying the invention, is indicated generally by the reference numeral 10. The target, 10 comprises a substantially vertical planar target triangle generally indicated 'by the reference numeral 11, a stabilizing tail structure or empennage generally indicated by the reference numeral ,12 at the base or trailing end of the target triangle 11, a spherical radar-reflector 13 symmetrically located relative to the target triangle 11 and empennage 12, a"pair of tracking flares 14 at the lateral extremities and an'identification smoke package 15 near the apex or leading end of the target triangle 11, and a bridle portion of a tow cable 16 connected to the center of gravity of'the aerial target 10.

The empennage 12 comprises a pair of generally hori- 7 and 18 with vertical stabilizing surfaces 19 and 29 connected to the lateral ends thereof, respectively.

rial which has suitable strength and bullet marking characteristics as will be understood by one skilled in the art. The two parts 22 and 23 are connected together by a central longitudinally extending beam arrangement generally indicated by the reference numeral 24 of a special configuration. Also the outer periphery of the target triangle 11 is provided with a generally U-shaped or channel-shaped edgeguard 25 connected thereto by suitable fastener means 26 such as rivets.

The central longitudinally connecting beam 24 is a composite construction comprising two generally wr-shaped and oppositely oriented channels 28 and 29, FIG. 4, which are vertically spaced by means of non-metallic material such as wood filler 30, FIG. 2. However, the wood filler 30 does not extend the full length of the target triangle 11 for reasons which will become apparent hereinafter.

More particularly, the vr-shaped channels 28 and 29 each have a generally horizontal extending face portion comprising laterally extending horizontal flanges 31, 32, respectively. Both of the channels 23 and 29 have a pair of parallel vertically extending legs 33 and 34, respec* tively, which form a channel-shaped structure. The juxtaposed parallel edges of the panels 22 and 23 are respectively inserted between the legs 33, 34 of the 1r-shaped channel members 23, 29, respectively, and secured thereto by suitable means 35 such as bolts and nuts. Preferably, the bolts 35 are disposed in bushings 38 in order to better protect the panels 22 and 23.

The 1r-shaped channel beams 28 and 29 which are spaced by the filler 30 are connected together by the suitable fastening means 35 along the length of the flanges 31 and 32 thereof.

The tow cable 16 is bifurcated at its outer end and connected to a pair of laterally spaced apart eyes 41. The openings in the respective eye connections 41 are disposed over a transversely disposed bolt 42 journaled at substantially the center of gravity of the target between the longitudinally extending 7r-Sl1aPt3d beams 28 and 29. The bolt 42 is journaled in a rectangular journal block 43 having a transversely extending cylindrical opening 44. In this manner the target triangle 11 is pivotally connected to the bifurcated end of the tow cable 16 and free to assume an attitude in the direction of air flow, as directed by the empennage 12.

The empennage 12, as pointed out, comprises generally the horizontal stabilizing surfaces 17, 18 and the vertical outboard stabilizing surfaces 19 and 20. It will be understood also that the target triangle 11 acts as a central vertical stabilizer.

The horizontal stabilizer, comprising the port or left hand stabilizer 17 and the starboard or the right hand stabilizer 18, are preferably formed of one generally rectangular piece which is preferably of the same material as the parts 22 and 23 of the target triangle 11. The leading and trailing edges of the horizontal stabilizers 1'7, 18 are protected by generally U-shaped or channelshaped leading and tailing edgeguard members 45 and 46, FIG. 1, similar to the channel members 25. The two channel members 45 and 46 are secured to the lead, ing and trailing edges, respectively, of the horizontal stabilizer members 17 and 18 by the suitable fastening means 26 such as rivets. The fastening means 26 are also utilized to secure the horizontal stabilizer members 17 and 18 between the spaced apart and opposed horizontal flanges 31, 32 of the 'ir-ShQPd beams 28 and 29.

The vertical stabilizers 19 and 20, which form the port or left hand stabilizer and the starboard or right hand stabilizer, respectively, are of substantially the same construction as the target triangle 11 and the horizontal stabilizers 17 and 18. The respective vertical stabilizers 19 and are similarly constructed and are compised of generally rectangular flat panels oriented so that the elongated part thereof extends vertically as seen in FIG. 2. Each of the vertical stabilizer panels 19, 20 have the peripheries thereof protected by generally U-shaped or channel-shaped edgeguards 51 which are appropriately secured thereto by the suitable fastening means 26. The vertical stabilizer 19 is connected to an outer edge portion of the horizontal stabilizer 17 by means of a longitudinally extending and generally horizontal 1r-shaped beam or connecting member 53 similar to the 1r-shaped members 28 and 29 referred to hereinabove. The outer edge of the horizontal stabilizer 17 is inserted between the parallel legs and bolted thereto by the fastening means 35. Similarly the vertical stabilizer 20 is connected to the juxtaposed outer or lateral edge of the horizontal stabilizer 17 by means of another 1r-shaped beam 53.

One of the advantages of using the split or dual vertical stabilizer type of empennage is that While only a very limited empennage surface presents itself to add to the total drag of the target triangle 10 a considerable amount of stability is derived therefrom. In this manner a large amount of surface area has been eliminated from the tow target which would add to its total drag, and as a result, the total drag of the tow target 10 does not increase proportionately with the relative increase in size of the target. Although the target triangle 11 and the empennage surfaces of the aerial target 10 are generally flat and there is no great amount of lift generated by towing the target at high speeds, there will be a certain amount of lift and good self-alignment characteristics due to the direct impingement of the airstream against the fiat surfaces which may be presented when the target 10 assumes an attitude at an angle to the slipstream or flow of air therepast.

In order to better balance the target 10 for aerodynamic purposes, the vertical spacing between the 1r-shaped beams 28 and 29 of the target triangle 11 is left free of wood filter at the forward end so that a ballast block 55 of the same thickness as the filler 30 and the horizontal stabilizers 17, 13 can be fastened therebetween in a suitable manner such as with the fastener means 35 which have been used throughout the target 10, FIG. 2. Preferably there is a longitudinal spacing between the trailing edge of the ballast block 55 and the filler 30 so as to provide for the attachment of the identification smoke puff package 15, referred to hereinabove. It is to be understood that any conventional type of smoke pufi package can be used if desired.

The tracking flares 14 are connected in a suitable manner parallel to the line of flight of the target triangle 11 and just opposite to the ar-shaped connecting beams 53 by suitable means, as best shown in FIG. 3.

If desired, a launching spike 56 can be connected approximately at the midpoint of one side, the underside, of the tow target triangle 11, FIG. 2.

In addition to or in lieu of the launching spike 56, a pair of generally parallel and laterally spaced ground support stabilizers 60 are attached to the lower corners of each of the vertical stabilizer members 19 and 20. Preferably, in the preferred embodiment of the invention, the ground support stabilizers 60 are made of a light metal tubing generally of a V-shape or in the shape of two sides of a right triangle. More particularly, each ground support stabilizer 60 has a vertically extending portion 60a and a generally forwardly and vertically upwardly extending portion 60b with the bight or connecting portion 600 being in the shape of an arc of a circle. The upper end of the tubing portion 60a is connected to the lower trailing edge of the stabilizer 19 by means of a generally U-shaped bracket 61, FIG. 2. The bracket 61 is connected together by the rivets 26 used to fasten the edgeguard 51 thereto. The uppermost end of the portion 60b of the ground stabilizer 60 is bent vertically upwardly so as to lay flush with the lower portion of the leading edge of the stabilizer 19 and is like-- wise clamped thereto by a U-shaped clamp 61 and se-v cured to the stabilizer 19 by rivets 26. It will be under-- stood that the bight portion or arcuate portion 60:: of

the guard 60 extends-vertically downwardly substantially 'the same-distance "as-the lower 'corner of the part 23 of the target triangle -11. The right hand guard 60 for the vertical stabilizer 20isof the same construction which utilizes identical brackets61 as described in con- .nection with the port stabilizer 19.

Another modification ofthe invention, FIG. 5, deals with the manner'in which the tow cable 16 is connected to the target triangle 11. More particularly, in lieu of the journal block 43, FIG. 4, an arcuate slot 70 is formed in the target triangle portion 22. Preferably the slot is formed in a metal plate 71 so as to provide adequate hearing surface for the transverse bolt 42. The slot 70 is generally arcuate and extends for generally a length equivalent to that of an arc of 90 degrees. One of the advantages of this arrangement as shown in FIG. 5 is that the bolt 42 of the tow cable 16 will always be coincidental with a line radiating from the center of gravity or C.G. of the target and the central axis of the cable 16 no matter what attitude or angle of attack the target 10 may take relative to the slipstream or the angle at which the cable 16 happens to be hanging. This is, of course, within the limits of the length of the are 70. In this manner, the center of gravity of the target 10 may shift slightly. Also, the target will be more or less self-aligning while in flight. In contradistinction thereto, the pin connection with a fixed location such as is shown in FIG. 2 is not self-aligning relative to a shift in the center of gravity, although the target 10 will tend to substantially align itself during flight.

Another important feature of the invention is the use of the spherical radar reflector 13 at the trailing end of the target 10. The spherical radar reflector 13 can be secured to the trailing end of the longitudinally extending 1r-shaped beams 28 and 29 in any desired manner as will be understood by one skilled in the art. The use of a radar reflector 13 is found desirable in this case because of the generally non-metallic construction of the target 10 in its preferred form. As a result, for gunnery equipment such as electronic computers used by aircraft today, a positive radar reflector for the acquisition by radar equipment will always be provided regardless of the actual material used in the construction of the target 10.

One of the advantages of the present structural configuration, which is very light weight and of low drag characteristic, is that in most radar scopes the observer can determine the exact attitude of the present invention. The reason for this is that the target 10* has a top view configuration, FIG. 1, that is considerably different from the side view, FIG. 2. This is not true for the twin-delta type of targets which are also handicapped by a high drag characteristic. Obviously in comparing FIGS. 1 and 2 it will be seen that the reflecting surface of the target A from above or below is considerably less than the reflecting surface provided from the sides as shown in FIG. 2. The same will be held true in regards to approaching the target from fore or from aft. As seen in FIG. 3, the spherical radar reflector 13 presents itself as a positive means for reflecting a signal to the radar equipment of the gunnery aircraft. Thus, the pilot can determine whether or not the target is being approached parallel to line of flight thereof from the radar scope. The towing aircraft, of course, will be in danger if the target 10 is approached from the aft end thereof.

From the foregoing, it is apparent that it is important that the pilot be able to determine the relative position of his aircraft relative to the target because fatal accidents and destruction to the towing aircraft may more likely occur should the approaching practicing gunnery aircraft approach the. target from the rear or from a dangerous angle above or below the towing aircraft.

While a specific embodiment of the invention has been shown and described, it is understood that the same is susceptible of many changes and modifications, as known to a person skilled in the art, and it is intended that all such changes and modifications comingwithin the scope of the appended claims he covered.

What is claimed is:

1. An aerial'target comprising, a planar and isosceles- .shaped target triangle with the trailing edgeof said trianglenormally being perpendicular to the lineof flight,

first means for connecting to the tow cable, second means revolvably connecting saidfirst means to said target about an axis through the center of gravity thereof and normal to said triangle, horizontal stabilizer means of small dimension in comparison to said triangle connected to said triangle and disposed perpendicularly to said trailing edge and to the plane of said triangle, and said horizontal stabilizer means having the leading edges thereof located to the rear of the center of gravity of the aerial target.

2. A high-speed stabilized aerial tow target for use with a tow cable having its outboard end bifurcated, comprising: a triangular target panel having one of its apices acting as the leading end and the opposite side thereof acting as the trailing end during normal flight, first means for connecting to the tow cable, second means revolvably connecting said first means to said target about an axis through the center of gravity thereof and normal to said panel, said panel having a pitch attitude during normal flight such that its upper portion is positioned within the bifurcated end of the tow cable thereby maintaining it in a substantially vertical position, horizontal stabilizers of small dimension in comparison to said panel fixed to said panel near the trailing end thereof and extending outward from the opposite sides thereof in such a manner that they are substantially horizontal during normal flight, and vertical stabilizers of small dimension in comparison to said panel fixed to said horizontal stabilizers near the outer extremities thereof in such a manner that they are substantially parallel to said panel; whereby a large vertical targe is provided with very little stabilizer surface drag.

3. An aerial target as set forth in claim 2, said second means comprising an arm pivotally connected at one end to said target and fixed at the other end to said first means.

4. An aerial target as set forth in claim 2, said second means comprising an arcuate slot means formed in said panel with the center of gravity of said target as its center.

5. A high-speed stabilized aerial tow target for use with a tow cable having its outboard end bifurcated, comprising: two triangular target portions, a pair of oppositely facing parallel qr-shaped beams disposed substantially horizontal during flight, each of said portions being secured on one side between the parallel legs of the respective vr-shaped beams so as to form a triangular target panel having the apex bisected by said vr-shaped beams acting as the leading end and the opposite side thereof acting as the trailing end during normal flight, means securing said ar-shaped beams together, first means for connecting to the tow cable, second means revolvably connecting said first means to said target about an axis through the center of gravity thereof and normal to said panel, said panel having a pitch attitude during normal flight such that its upper portion is positioned within the bifurcated end of the tow cable thereby maintaining it in a substantially vertical position, a horizontal stabilizer of small dimension in comparison to said panel fixed between said 1r-shaped beams near the trailing end of said panel and extending outward from the opposite sides of said panel in such a manner that it is substantially horizontal during normal flight, and vertical stabilizers of small dimension in comparison to said panel fixed to said horizontal stabilizer near the outer extremities thereof in (References on following page) References Cited in the file of this patent UNITED STATES PATENTS Skinner Sept. 20, 1949 Troxel Jan. 29, 1957 Cotton Sept. 3, 1957 Bates Oct. 15, 1957 Seeley Jan. 28, 1958 Great Britain Sept. 21, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,030,111 April 17, 1962 WilliamB. Hendershott It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3 line 58 for "tailing" read trailing column 4 line 34 for "filter" read filler 5 column 6, line 36 for "targe" read target Signed and sealed this 4th day of December 1962.

(SEAL) Attcst:

DAVID L. LADD ERNEST W. SWIDER Commissioner of Patents Attesting Officer 

